Separation of stereoisomeric cyclic carboxylic acids
US4196304A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 6, 1978 |
| Grant date | Apr 1, 1980 |
| Priority date | — |
| Expiry date | Mar 6, 1998 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C51/487
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A process for the separation of the stereoisomers of a stereoisomer mixture of a cyclic carboxylic acid of the formula ##STR1## in which R.sup.1 and R.sup.2 each independently is hydrogen, halogen, C.sub.1 -C.sub.6 -alkyl or C.sub.2 -C.sub.6 -alkenyl, PA1 R.sup.3 is alkyl, alkenyl or alkynyl having up to 6 carbon atoms and optionally substituted by halogen, or alkoxycarbonyl having up to 5 carbon atoms, or is aralkyl or aryl, or PA1 R.sup.1 plus R.sup.2, or R.sup.1 plus R.sup.3, together with the adjacent C atom, form a carbocyclic ring, PA1 R.sup.3 and COOH are cis or trans to one another and the COOH group is in the exo or endo position if R.sup.1 and R.sup.3 together form a ring, and PA1 n is 0, 1 or 2, which comprises contacting a weakly alkaline, aqueous solution of the stereoisomeric mixture with a non-polar organic solvent, whereby the cis or endo isomeric free acid enters the organic solvent while the trans or exo isomer remains in the aqueous solution as a salt, and separating the aqueous solution from the organic solvent, thereby to separate the isomers. Preferred acids are cyclopropanecarboxylic acid derivatives, the aqueous solution is preferably buffered to a pH of abo…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.